We’re only mid-week, but it’s already been a big one for human-induced earthquakes.
On Tuesday, scientists from Southern Methodist University added to the growing body of research linking small earthquakes to oil and gas wastewater disposal. That body of research is particularly important to the popular but controversial process of hydraulic fracturing, or fracking, which produces significantly more wastewater than conventional drilling.
On the same day, Oklahoma’s government announced that it would officially embrace that large body of scientific research, and start figuring out how to deal with its growing earthquake problem. In the last decade, Oklahoma has experienced a dramatic increase in earthquakes — an increase that has happened in tandem with the spread of wastewater disposal from fracking operations across the state.
CREDIT: OKLAHOMA GEOLOGICAL SURVEY
The research published by SMU scientists on Tuesday is similar to what we’ve seen before. Published in the journal Nature Communications, it links a series of small earthquakes in Azle, Texas to oil and gas activity — specifically, the process of injecting drilling wastewater underground. According to the research, the faults that shifted below Dallas-Fort Worth “have not budged in hundreds of millions of years.”
What makes the Texas study a bit different than other research linking human activity to seismic events is that it suspects wastewater injection alone is not causing the quakes. Instead, it asserts that there’s a specific thing workers do when extracting fuel and performing wastewater injection that may be triggering them.
According to the research, quakes may be made more likely when workers extract gas and groundwater from one side of a fault line, then inject water back into the ground on the other side of the fault. That is slightly different than what other research has suggested — that wastewater injected anywhere near fault lines can change the stress of those faults to the point of failure, causing earthquakes.
Still, the basic idea is the same: human activity, via oil and gas watewater injection, is the most likely explanation for these unusual strings of earthquakes happening across the country.
“It’s what we figured all along, it’s not really new news to us,” said Azle Mayor Alan Brundrett, according to NBC’s Dallas affiliate. “It’s just confirming our suspicious that we’ve had.”
The fact that scientists haven’t been able to make definitive statements about oil and gas activity’s connection to earthquakes has been the main argument of industry supporters when these issues arise in states, particularly Texas and Oklahoma. The Texas Railroad Commission, which regulates oil and gas activity, has been resistant to concerns that fracking activity may be causing quakes in the state. In response to Tuesday’s study, the agency’s staff seismologist Craig Pearson said it “raises many questions with regard to its methodology,” but declined to say exactly what those questions were before meeting with the researchers.
In saying oil and gas was likely responsible for the state’s earthquake epidemic, the state launched a website detailing why earthquakes are happening and what the state is doing to stop them.
“Oklahoma state agencies are not waiting to take action,” the website reads. “The Oklahoma Corporation Commission has been implementing evolving directives for wastewater disposal operators, known as the ‘traffic light’ system, based on the general view that injection of disposal of wastewater into the basement rock presents a potential risk for triggering seismicity.”